Another option is to develop server side AI that can detect some non human behavior or behavior patterns that are cheats. It's not full protection but for sure more appropriate than putting rootkits on the client side.
here is another idea: proper ranking of player abilities! crazy right? something so simple should be a day-one feature right? that would put all the hackers together and they could even compete in their own hacking league... 100% of clients satisfied!
now think about game companies failing to put that single feature to work correctly, what changes do you think a AI that detect human behaviour have or working well in that space? :(
